The Pros of Cons of Genetic Screening
The subject of genetic engineering has always been a controversial one, that has divided opinion for years, although in today’s society it is more important than ever. Although the possibilities of genetic manipulation have been theorised as early as the 17th century and H. J. Muller was artificially mutating genes of Drosophila with x-rays in 1927, the experiment that really brought the possibilities of genetic engineering to public attention was Dolly the sheep, the first mammal to be cloned from an adult cell, in 1996. Although the first IVF baby was born long before this, in 1978, the controversy that surrounds it is more relevant than ever, since this milestone in genetic history.
Since then GM crops, human cloning and genetic screening have all been issues of concern not just for scientists and religious leaders, but by members of the public too.
What is Genetic Screening?
Genetic screening normally involves two processes IVF (in-vitro fertilisation) and PGD (Pre-implantation genetic diagnosis). In-vitro Fertilization basically involves uniting the egg and the sperm outside of the of the body. The fertilised embryo can then be transferred into the uterus and pregnancy can begin. Pre-implantation genetic diagnosis, or at least it’s future implications, is the more controversial of the two stages, and it involves analysing the cells of the embryos before they are transferred back into the woman for genetic disorders which could lead to inherited diseases.
The process of IVF is carried out in several stages over a number of days. Firstly, the woman is injected with hormones to make her super ovulate. The follicles are then located in the ovary and the eggs removed with a hollow needle. Immediately following the retrieval, the eggs will be mixed in the laboratory with the man’s sperm, causing fertilisation in successful cases. The fertilized eggs are kept in the clinic under observation to ensure optimal growth. Once the embryos are ready, they can be transferred into the uterus.
A flexible tube called a catheter is inserted into the uterus, where the embryos will be deposited. In PGD a single cell is removed from an 8-cell embryo that has been created via IVF through an opening in the outer protective wall. The microscopic procedure is carried out precisely, without damaging the embryos ability to continue to develop normally (because at this early stage of development none of the embryo cells have become specialized, or adapted for their tasks). The cell is then analysed in the lab for the presence of genetic disorders.
The Advantages and Disadvantages of IVF and PGD
Although the initial process of IVF is less cause for concern to those who oppose the idea of genetic screening, it comes with reasons of it’s own to cause such a backlash. Obviously, the benefits are huge – IVF greatly improves chances of pregnancy in infertile couples who had little chance of starting a family. Embryos can be implanted directly into the womb, meaning that women with damaged or blocked fallopian tubes can still become pregnant. Finally, unlike some other methods, such as Donor sperm insemination (TDI), Couples can have a biologically related child.
However, one downside of IVF is that the high price of the procedure, combined with it’s relatively low success rate, makes it a constant drain on taxes. According to statistics from BBC NEWS, the overall live birth rate per cycle is 15.2% (for sub-fertility). Other sources give anything between 20-39%. The chances of pregnancy also decrease with age, as well as factors like weight and smoking, so it is not always the solution to infertility. More importantly, there is some concern about emerging evident suggesting abnormalities in offspring.
Obviously IVF is a great benefit for couples unable to have children what is seen as the traditional way. Previously, they may have had to use donor eggs or sperm, or adopt. Although this would allow them to raise a child, most parents would rather have their own biological child, and with IVF, despite some shortcomings, this is now a possibility. There is not so much opposition to IVF itself, apart those who believe conception should only occur naturally.
With Pre-implantation genetic diagnosis, despite the strong opposition from many faces of society, there are many possibilities beneficial to life and science. It could prevent degenerative genetic diseases that have been destroying humanity for years, like Huntington’s and Cystic Fibrosis. Parents could determine the sex of their baby to prevent passing on a sex-linked disorder. PGD before impregnation can help prevent miscarriages. With PGD in full-flow comes the distinct possibility that one day in the future, genetic diseased could be eliminated entirely from the gene pool.
However, the public, religious and scientific reaction to each new discovery in the field are not unjustified. Downsides to PGD, as with IVF, include the high price of the process, as well as more difficult ethical and moral problems. PGD could so easily be abused. Why stop at eliminating diseases, when you can also determine sex, eye and hair colour, allergies, or many more medically unrelated, insubstantial aspects that are effectively messing with the genetic-make up of your offspring.
An entirely plausible future has been envisioned by many where embryos are chosen for aesthetic or desirable qualities. Topics like ‘Designer Babies’, and the controversy in the newfound choice of sex of your child frequently hit the headlines, and with good reason. Additionally to this moral debate. PGD doesn’t guarantee that a baby won’t have other birth defects or difficulties, and many of these so-called defective genes confer advantages of a different nature e.g. the sickle cell anaemia allele protects against malaria in countries where it is rampant, and several neurological defects can result in high levels of intelligence.
PGD is an undoubtedly useful procedure. It can help to identify potentially debilitating illnesses or inherited disorders, and also determine the sex of a baby to allow parents carrying a sex-linked disorder gene to procreate without passing on a genetic disorder to their children. Of course, starting from the choice of sex in determining some quality of life, there is a dangerous potential for parents to choose embryos based on aesthetic qualities. While this is obviously morally wrong, there are currently very tight laws on genetics and it looks unlikely it will happen any time soon. Further more, part of a consultation carried out by the Human Fertilisation and Embryology Authority (HFEA) showed that 69 per cent of Britons believed that unrestricted sex selection should not be allowed and that 80 per cent believed that PGD should not be allowed for non-medical reasons.